DE60021040T2 - Flexible medical stent - Google Patents

Abstract

The present invention is directed to a radially expandable medical stent 3 having a chevron or "maple leaf" design geometry characterized by improved scaffolding, hoop strength and longitudinal flexibility. Also described are methods of making and deploying the stents. <IMAGE>

Description

The The present invention relates to implantable intravascular stents to maintain vascular patency in humans and animals. In particular, the present invention directed to a balloon expandable stent by an improved Framework, improved ring strength and improved longitudinal flexibility.

These In particular, this invention relates to intraluminal endovascular stent implantation Method by which a prosthesis is inserted into a body tube and expanded, around a collapsed vessel wall again to open and to prevent the wall from collapsing back into the lumen. endovascular Stent implantation is particularly useful for arteries, which are blocked or narrowed, and is an alternative to surgical Activities, which aim to bridge the occlusion or occlusion.

percutaneous Transluminal coronary angioplasty (PTCA) is used to treat the To enlarge the luminal diameter of a coronary artery or coronary artery, partially or completely through an accumulation of cholesterol fats or an atherosclerotic Plaque is blocked. Conventionally a guidewire through the vascular System controlled to the treatment site. Then, for example, a Guide catheter over the guidewire can be propelled and a balloon catheter can within the Guide catheter over the guide wire be driven forward. The balloon at the distal end of the catheter is inflated, causing the location of the stenosis to widen. However, the dilatation of the occlusion may include valves, fissures and sections form, in which a restenosis of the dilated vessel or even Perforations of the vessel wall threaten. The implantation of a stent can provide support for such valves and sections provide and thereby prevent reclosure of the vessel, or a patch repair for one provide perforated vessel wall, until a corrective operation can be performed. It has also been shown that the use of intravascular stents the occurrence of a Restenosis after angioplasty can decrease noticeably, causing the likelihood is reduced that a second angioplasty procedure or a surgical bypass surgery is necessary.

A implanted prosthesis, such as a stent, may be additional activities prevent and vessel vascularity obtained by mechanically supporting the expanded vessel, a re-closing to prevent the vessel. Stents can also be used to repair aneurysms, artificial To support vessels as pods for vessels or Repair sections. Stents are suitable for the treatment of any body lumen, including the vas deferens, head of the gallbladder, the prostate gland, the Trachea, bronchi and liver. The body lumens range in diameter of small coronary vessels of 3 mm or less up to 28 mm in the aortic vessels. The invention is directed acute and chronic occlusions or reclosures of Body lumen.

One Stent is conventional a cylindrically shaped device made of wire (wires) or out of a tube and is intended to be permanent To serve a prosthesis. A conventional one Stent ranges in length from 5 mm to 50 mm. A stent becomes radial in a body lumen compressed Configuration towards a radially extended configuration, which allows the stent to a body lumen to put on and support it. Optionally, a balloon of suitable size and with appropriate pressure used to the lesion before placing the stent in its intended location.

Of the Stent can be radially self-expanding or he can by use an expansion device be expandable. The self-expanding Stent is made of a resilient material, while the device expandable stent made of one material is manufactured, which is plastically deformable. A plastically deformable Stent can while implanted in a single angioplasty procedure, by using a balloon catheter that has a balloon squeezed on the balloon Stent houses. The stent expands radially when the balloon is inflated, causing the stent to come into contact with the Inside of the body lumen occurs, creating a supportive relationship forms the vessel walls.

The Erection or deployment is effected after the stent percutaneously introduced, transported transluminal and at a desired location by means of a guide catheter is arranged. In the case of a balloon expandable stent is the delivery catheter a balloon catheter and the stent is set up, when the balloon is inflated. The stent remains as a permanent one Scaffolding, after the balloon withdrew is. A balloon that is able to withstand the relatively high inflation pressures may be preferred for stent deployment, because of Stent against the inner walls of the Artery needs to be brought so that it fully expands, which excludes the fact that the ends of the stent in the canal hang down and promote the development of a thrombus.

conventional Angioplasty balloons divide into high, medium and low Pressure ranges on. Low-pressure balloons are those whose nominal pressure at Burst under 6 atmospheres lies. Medium pressure balloons are those whose nominal pressure when bursting between 6 and 12 atmospheres lies. High-pressure balloons are those whose nominal pressure at bursting is above 12 atmospheres. The pressure at bursting is determined by the material selection, the wall thickness and the strain strength certainly.

Previous Structures called stents or intraluminal vascular grafts used include annular Springs made of stainless steel or stainless steel, spirally wound Ring springs made of a shape memory alloy are, expandable metal stents that formed in a zig-zag pattern are diamond-shaped, rectangular shaped and other mesh and Non-mesh designs. exemplary Stent devices are U.S. Patent 5,776,161 issued to Globerman, the Pinchasik et al. U.S. Patent 5,449,373, Fischell et al. U.S. Patent 5,643,312 to Lau et al. granted U.S. Patent 5,421,955 and the for Victor issued U.S. Patents 4,649,922, 4,886,062 and 4,969,458 disclosed.

problems which are to be solved in designing stents include (a) inappropriate Radial force to maintain the extension, (b) unsuitable tissue scaffolding at the Wall, (c) longitudinal stiffness before extension, which is the supply of the Stents adversely affected, (d) impossibility to create a diameter to reach the enlargement, which is small enough to go through tight lumen (e) in the case of balloon-expandable stents, unacceptable mechanical stress or strain levels in the dilated stent, (f) expanding the stent ends during stent delivery, and (g) longitudinal shortening of the stent as a consequence of radial expansion.

Unfortunately Many of these problems result from or are aggravated by the common conflicting goals of the stent design. For example it is desired a high level of Scaffolding in to show the stent when the stent expands in its radial size is, making the vessel wall a has consistent support. However, it is also desirable to have a small, relatively smooth fed profile (sometimes referred to as a "pinch diameter") when the stent is attached to the catheter to the stent and the catheter to enable lesions to cross from a small diameter. The person skilled in the art recognizes that when a stent with a very small diameter fed radially expands is, its structural elements continue to divide and openings generate the amount of available scaffolding for Support reduce the vessel. Such a stent may also be a reduction of outward radial forces (Hoop strength) show through the stent after expansion within the Lumens are generated. The larger window area and therefore the worse body lumbar framework is reduced the efficiency against recurrent restenosis. The reduced outward-facing personnel can also be problematic if the stent the wall of the lumen not firmly recorded.

One another example of the conflicting goals of the stent design concern attempts to an improved framework and improved longitudinal flexibility during catheter delivery reach, since no sufficient framework achieved, if only a few supporting structural elements available. However, the incorporation results from too many structural ones Elements in a loss of stent flexibility in both the squeezed as well as the expanded state.

One Attempt to address the high bending strains / stresses in a radially expandable stent is disclosed in U.S. Patent No. 4,830,003 (Wolff et al.). described in which the stent consists of a number of essentially straight wire segments are welded together at their ends, around a zigzag-shaped Form stent when expanded. By the use of essentially straight wires, can they Bending stresses / strains that interfere with the bends in an integral Wire-formed stent body connected are to be avoided. However, disadvantages associated with this approach include the cost of producing the stent by welding. Lower welds also the allowable voltage levels in the stent, thereby reducing its Fatigue life and compressibility to the feeder limited is. Other disadvantages are that the length of the stent is different from the compressed state to change the advanced state significantly, creating an accurate Arrange the stent at the desired location within a body lumen is more difficult.

Globerman US Patent 5,776,161 relates to a variety of these problems. Globermann discloses an expandable stent that has a small exit diameter, flexibility along its longitudinal axis prior to dilation, and minimization of rigid local stresses in the stent material through the appearance of rotational interconnections having minimal stresses during stent dilation. The stent has substantially the same length before and after dilation and is longitudinally flexible when contracted so that it is easier to feed. It will ever however, additional improvements in longitudinal flexibility in the crimped stent during delivery and scaffold after delivery are desired.

The Document WO-99-40876 describes a tubular stent in which the two Rings through ipsilateral M-frame joints attached to each other.

It It is an object of the invention to provide a radially expandable stent Implantation within a body lumen to provide improved ring strength and scaffolding properties.

It Another object of the invention is a radially expandable stent to provide a reduced crushed diameter while, while it maintains a satisfactory longitudinal flexibility, framework and ring strength.

It is another object of the invention, a radially expandable To provide a stent having improved longitudinal flexibility, around tortuous lumens and lesions as well as to allow implantation into curved lumens.

It is another object of the invention, a radially expandable To provide stent having a reduced end widening.

These and other objectives are achieved by the radial expandable stent Achieved invention, which has many advantages over known devices.

This invention provides a medical device comprising: a catheter and a radially expandable stent attached to the catheter, wherein the stent
a hollow cylindrical body comprising first and second rings extending around the cylindrical body, each ring comprising a wavy series of peaks and valleys formed by braces connecting curved alternating mountain and valley segments within the ring; the struts comprising a first curved segment which is substantially symmetrically curved about a single circumference of the stent such that the peaks and valleys within a ring form a nested zig-zag pattern; characterized in that
the first and second rings are directly and firmly connected to corresponding opposite mountain and valley segments.

Of the radially expandable stent of the invention shows an improved Resistance to fatigue fracture due to Bending loads, an improved scaffold, and improved hoop strength are among those able to lesions otherwise, without the help of additional Rotation methods are difficult to achieve, and is essential with one linked to a lower shift rate. The radially expandable Stent of the invention may be a plastically deformable, by a Device expandable stent, such as a balloon expandable Stent, or a ra dialer self-expanding stent that comes from a elastic resilient material is made.

In one embodiment, the present invention provides a medical device comprising a catheter and a stent attached to the catheter, the stent being a radially expandable stent for implantation within a body lumen in the form of a longitudinally extending substantially tubular body defines a passage having a longitudinal axis. The stent is radially compressible into a compressed diameter and radially expandable to an expanded diameter. The tubular body includes a plurality of annular ring members disposed sequentially along the longitudinal axis of the stent, each of the ring members having proximal and distal ends defining a longitudinal length along the longitudinal axis. Each of the ring members includes a plurality of peaks and valleys disposed in the proximal and distal ends of the ring member so as to be circularly disposed on the ring member, the struts connecting the peaks and valleys at opposite ends of the ring member. The high point on a mountain and the low point in a valley are referred to here as mountain and Talextrempunkte or - vertices. The struts are curved or bent around a circumference of the stent in a manner that allows the struts, mountains and valleys to remain substantially at the surface of the stent. In the compressed state, the curved struts of a ring member are arranged in a nested fashion, with a pattern defined by the curved struts and the peaks and valleys conventionally described as a "zigzag" or "maple leaf" pattern. The struts can be packed close together in a nested arrangement when the stent is squeezed onto the balloon catheter. By "nesting", "nested" or "nesting" it is meant that the elements are conformally arranged so that they can be in very close proximity when the stent is squeezed onto the catheter, but without substantial contact, which enhances the ability of the catheter various elements could influence, in relation to move toward each other when the stent and the catheter are driven by a tortuous body vessel. In a preferred embodiment, the longitudinal length of the two end rings is shorter than the longitudinal lengths of the other rings to reduce the final expansion during advancement, delivery and transport of the stent.

Of the Stent also includes at least one fixed or integral Connection between the adjacent ring elements in the tubular body. Preferably Two or three such connections occur between adjacent ones Ring elements on. traditionally, are less than about the half the mountains and the valleys occupied on a ring of longitudinal links. However, that is the number of longitudinal links is not in any one Way limited provided, but the optimal number of longitudinal connections is generally due to the number of mountains and valleys in affects the rings, the diameter of the stent in the compressed form and the radial expanded form and, among other things, the longitudinal length of the stent and its intended use. A stent can be one or more types of longitudinal compounds containing the form of integral or fixed connection areas between one Take mountain on a ring and a valley on an adjacent ring. Longitudinal connecting elements can be parallel to the longitudinal Be the axis of the stent or you can spaced from the longitudinal axis of the stent. The longitudinal Connections are preferably arranged to shorten the Avoid stents when the stent is radially expanded. Furthermore are longitudinal connections preferably arranged to the longitudinal flexibility to promote. To the Example connect longitudinal connections conventionally two adjacent ring elements and do not extend to additional To connect ring elements. Therefore, in successive rings longitudinal connections preferably "out of phase" or offset with respect to each other, as defined below to improve the longitudinal or "bend" flexibility of the stent. The use of two or three longitudinal connections between a pair of adjacent rings is conventionally preferred to to achieve the greatest bending flexibility.

If Stents propelled by turns of a vessel they are bending forces exposed to the longitudinal stresses in the stent components can generate. If the movements of longitudinal connecting elements, the through these bending forces are caused, the ring elements from their outer or crimped positions raise, the stent can be radially increased, in particular to its ends (i.e., in end widening) and may be in difficulty a narrow lesion to cross. The present invention reduces or prevents premature radial expansion of one or more ring elements while the feeder of a stent to a location in a body lumen by inserting curvatures in the struts of the ring elements. The curved braces are to one elastic longitudinal movement capable of controlling the disposition The stent increases, yielding longitudinally when exposed to bending forces is like those that during the feeder of the stent and a catheter through a tortuous coronary artery occur.

Of the Need for spacing between the components in the crimped Condition must be against the need for providing a powerful scaffold Vessel, that to be weighed. In the present invention can the curved Form of struts provide the spacing necessary for nesting of the ring and the longitudinal connections is needed, by making the ring in a substantially circular direction by a distance is extended, which allows the stent to be squeezed to a small diameter on the catheter. When the stent is in its expanded state, a vessel is provided framework favors, because the struts do not completely straighten, but in the essentially remain in the circumferential direction partially curved. The easy curved Struts result in small versatile cells, which means both the scaffolding as well as the ring strength improved is. Because of their inconsistent shape, these allow non-rectangular Cells to protrude through the opening of a smaller area of the vessel wall, as is possible by square cells that have a similar Circumference or surface area which results in a better framework. A conventional one expansion ratio for one Radial expandable stent of the invention is about 2.5 to approximately 3.5, but can be up to about 6.0. Furthermore, the curved shape of the struts decreases the risk of a displacement of the compressed balloon expandable Stents when fed is, in terms of a comparable stent with straight braces. In a ring of a stent of the invention, each strut forms a V-shaped curvature which is symmetrical to a perimeter of the stent. The "V" therefore shows in the circumferential direction Rich. If the stent is squeezed on the balloon, the V-shaped curvature of the longitudinal movement of the stent relative to the balloon, because the corners of the strut provide easy orientation in the circumferential direction exhibit.

Different embodiments of the medi The device of the invention further comprises one or more of the following features: (a) a zig-zag pattern in a stent annulus element that is "in phase" with the zigzag pattern in an adjacent stent annulus element (b ) a zig-zag pattern in a stent annulus element that is "out of phase" with the zigzag pattern in an adjacent stent ring element, (c) a zigzag pattern in a stent annulus element that ""inphase" with the zig-zag pattern in an adjacent ring element and "out of phase" with the zig-zag pattern in another adjacent ring element of the stent, (d) a zig-zag pattern in a ring element of the stent parallel to the zig-zag pattern in an adjacent ring member of the stent, (e) a zig-zag pattern in a stent annulus element that is antiparallel to the zigzag pattern in an adjacent stent annulus member (f ) a zigzag pattern in a ring element of the stent, the par allel to the zig-zag pattern in an adjacent ring element of the stent and antiparallel to the zigzag pattern in another adjacent ring element of the stent, (g) integral longitudinal joints representing the extreme point of a mountain in a ring element (h) longitudinal links connecting a strut of the one stent-member of the stent to a strut of an adjacent stent-member of the stent, (i) ring members which are elongated from a single stent (j) ring members comprising a plurality of connected, closed structures; (k) ring members having circumferentially successive peaks and valleys alternately to the first and second circumferential members; Ring elements are arranged around the circumference of the tubular body, (l) ring elements, d ie pairs of peaks and valleys arranged at the distal and proximal ends of the ring element along a line parallel to the longitudinal axis of the stent; (m) at least two ring elements having different longitudinal lengths; (n) at least one end ring element , which is designed so that it can accommodate a radiopaque marker. The terms "in-phase,""out-of-phase,""zig-zag,""parallel," and "antiparallel" are defined or embodied below.

One Method of using a radial expandable stent The invention may include propelling the distal end of a delivery device and the stent through a body lumen include followed by positioning the stent at a desired location Place within the body lumen.

Of the Stent can be made of a tube that is made with lasers or other techniques well known to those skilled in the art. The initial one Pattern cut into the tube comprises longitudinal connection and ring elements which interact with each other. Between the stent components is a sufficient spacing provided to allow the stent on a catheter to be squeezed without generally jamming the ring and the elongated one Connecting components cause each other, whereby a bending of the stent without a malfunction the pinching of the ring components on the catheter during the Staging the stent is made possible by tortuous coronary arteries.

These and other features and advantages of the present invention below, by way of example only, with reference to the drawings described.

1 shows a plan view of a balloon catheter with a stent attached to the balloon portion of the catheter.

2 to 4 Fig. 11 are flattened plan views showing portions of stents made in accordance with the present invention. Each of the stent patterns shown would be curved into a cylindrical shape and onto the balloon catheter, as in FIG 1 be represented, squeezed or become.

5 Figure 11 is a flattened plan view illustrating various design features of stents made in accordance with the present invention or otherwise.

6 to 8th Fig. 2 are flattened plan views illustrating stents made in accordance with the present invention or otherwise. Each of the stent patterns shown would be curved into a cylindrical shape and onto the balloon catheter, as in FIG 1 be shown squeezed or become.

With a view to 1 includes the medical device 1 the present invention, a catheter 2 and a stent 3 that is on the catheter 2 is attached in a non-expanded state. The stent 3 has a hollow cylindrical body having a plurality of rings about a longitudinal axis 8th is made. As shown, the stent is 3 over a balloon 4 that is attached to the catheter 2 near the distal end of the catheter 2 attached, bruised. The stent 3 can include a variety of configurations, as in the 2 to 5 Shown in an open and flattened configuration as shown in FIG non-expanded and uncompressed state appear. The balloon 4 can be virtually any balloon that is suitable for angioplasty and is capable of being inflated to a pressure of six atmospheres or more. A preferred type for the balloon 4 is a multi-fold balloon that allows the stent to expand evenly and is about the same length as the stent. In addition to the squeezing, the stent 3 on the balloon 4 by retention techniques well known to those skilled in the art.

Now look up too 2 each of the rings extends 10a C in the circumferential direction around the cylindrical body of the stent 3 and includes a wavy series of mountains 11 and valleys 12 , The wavy mountains 11 and valleys 12 The Rings 10a -C are through opposite curved mountain and valley segments 13a -B trained to each other by bracing 14 are connected. The struts 14 also comprise two opposite curved segments 15a b. As in 2 is the first curved strut segment 15a in a central section of the bracing 14 arranged, and a second curved brace segment 15b is near or adjacent to a curved valley segment 13b arranged. The first curved brace segment 15a is essentially symmetrical to a line 17 perpendicular to the longitudinal axis 8th of the stent. The curved brace segment 15a allows nesting of struts within a ring and promotes longitudinal flexibility as the stent is delivered to the catheter; the curved brace segment 15b further facilitates nesting to achieve even smaller pinch diameter. The inconsistently shaped cells passing through mountain and valley segments 13a -B and curved braces 14 are defined also provide a powerful framework after deployment. As it is from the entire stent design in 2 easy to recognize, the braces alternate 14 in the circumferential direction around the rings 10a -C around, so for any other bracing 14 the second curved strut segment 15b near or adjacent to the curved mountain segment 13a instead of the curved valley segment 13b is arranged. The resulting form of individual mountains 11 and valleys 12 is that of an asymmetrical hairpin. Due to the alternating nature of the mountains 11 and valleys 12 by bracing 14 is the configuration of each ring 10a -C the one of constant modified zig-zag. Furthermore, as a result of conforming nesting within a particular ring 10a -C the bracing 14 is the zig-zag pattern around a perimeter of the stent 3 curved to form a zig-zag or nested "V" shaped pattern. In relation to each other are the successive rings 10a -C, in 2 in a parallel zig-zag pattern. The parallel zigzag pattern in the top view in 2 results from conforming nesting of all struts 14 in each of the rings 10a -C in a single uniform circumferential direction (ie either all struts are 19 nested clockwise or all struts 14 are nested counterclockwise). Furthermore, in the configuration, as in 2 is shown, the rings 10a C is oriented such that each ring is a mirror image of the ring (s) adjacent to it. Wavy mountains 11 and valleys 12 The Rings 10a -C are therefore arranged so that mountains 11 of the ring 10a longitudinal with valleys 12 of the ring 10b are aligned. As the term is used herein, two or more components of the stent are 3 "longitudinally aligned" if a line (eg line 18 in 2 ) drawn through the components substantially parallel to the longitudinal axis 8th of the stent 3 is. It should be appreciated that the invention is not limited by the orientation of a ring relative to an adjacent ring, ie the rings 10a -C may be arranged to be mirror images of each other as in 2 is shown, or they can become pairs of mountains 11 and valleys 12 be arranged in an "in-phase" relationship to each other, as described below with reference to FIG 3 is described in more detail, or they may be arranged in an alignment of the rings to each other between these positions.

Continuing with respect to the 1 and 2 are the rings 10a C by two short, substantially straight longitudinal links 16 shown connected together. In the in 2 The illustrated configuration is the integral longitudinal connections 16 parallel to the longitudinal axes 8th of the stent 3 and connect adjacent rings 10a -C at the extreme points of longitudinally aligned pairs of hills and valleys 11 / 12 , The number of longitudinal connections 16 between two adjacent rings is preferably two or three, but may be more. Preferably, no more than one longitudinal connection 16 with a mountain 11 or a valley 12 connected. A longitudinal connection 16 that extends between a first ring and an adjacent second ring does not extend to a third ring. This design feature makes the connection points between opposing mountains 11 and valleys 12 to "dead ends" in the longitudinal extent of the stent 3 and allows transmission of the bending forces from the short straight longitudinal connections 16 to the curved bracing segments 15a and 15b , The curved struts therefore absorb the bending forces generated by the longitudinal joints 16 are transferred, the short and / or stiff. Because they are straight and longitudinally aligned mountain and valley pairs 11 / 12 Integrate integrally, the longitudinal joints 16 be quite short, eg about 0.1 mm in length. Short longitudinal connections provide an improved scaffold. A radiopaque marker 9 is with the ring 10a within a circular land or ground section 19 connected to a central section of the struts 14b is arranged. The struts 14a and 14b are shaped so that the radiopaque marker 9 does not bother the ring when the stent 3 on the balloon 4 of the catheter 2 squeezed.

With view on 1 and 3 are in a further embodiment of the invention successive rings 20a -C are arranged in an anti-parallel zig-zag configuration with respect to each other. The antiparallel zigzag pattern in top view 3 results from the alternating nature of the conforming nesting direction of the struts 24 on successive rings 20a c. More precisely, the braces are 24 of the ring 20a and the ring 20c nested circumferentially counterclockwise while the struts 24 of the ring 20b nested in a clockwise direction, where is generated by the antiparallel zig-zag pattern. Furthermore, in the in 3 illustrated embodiment mountains 21 and valleys 22 however, as described above, the stent design is not limited by the relative orientation of one ring relative to its adjacent ring (s). The through the mountains 21a -C drawn line 28a is substantially parallel to the longitudinal axis 8th of the stent 3 , Similarly, the through the valleys 22a -C drawn line 28b substantially parallel to the longitudinal axis 8th of the stent 3 , The mountains 21a -C of the rings 20a C are therefore aligned longitudinally to one another; in a similar way are the valleys 22a -C of the rings 20a -C longitudinally aligned with each other, whereby the in-phase relationship between the rings is defined. The Rings 20a C are by two short, substantially straight longitudinal connecting elements 26 shown connected together. In the in 3 illustrated configuration are the longitudinal connecting elements 26 not parallel to the longitudinal axis 8th of the stent 3 but instead necessarily spaced in relation to it, because the connected pairs of peaks and valleys 21 / 22 are not longitudinally aligned, as they would be in a mirror-image configuration, as in FIG 2 is shown. In the in-phase ring configuration, as in 3 is shown, is the mountain 21d of the ring 20a "circumferentially adjacent" to the valleys 22d and 22e of the ring 20b Are defined. Similarly, the mountain is 21b of the ring 20b in the circumferential direction adjacent to the valleys 22c and 22f of the ring 20c , The longitudinal connection 26a between the mountain 21d on the ring 20a and the circumferentially adjacent valley 22d on the ring 20b is essentially parallel to the struts 24 that with the mountain 21d and the valley 22d are linked. Similarly, the ion is longitudinal compound 26b between the mountain 21b on the ring 20b and the circumferentially adjacent valley 22c on the ring 20c essentially parallel to the struts 24 that with the mountain 21b and the valley 22c are linked.

With a view to 4 this shows a design that does not fall within the scope of the invention. Successive rings 30a -B are arranged in a parallel zig-zag configuration with respect to each other and are oriented as mirror images of each other, as in FIG 2 is shown. The Rings 30a -B are with turning points 5 on some struts 34 intended. A turning point 5 is near a first curved brace segment 35a arranged, with the curved strut segment in a central portion of the strut 34 is arranged. At every turning point 5 a portion of the ring extends substantially in the circumferential direction (generally with 37 designated) for a short distance. A longitudinal connecting element 36 is at one end at the turning point 5a on a ring 30a and also at a second end at a second inflection point 5b on a neighboring ring 30b bound. The turning points 5a and 5b are aligned longitudinally to each other. The extension of a longitudinal connector between the central portions of the struts on adjacent rings has certain advantages over extending the longitudinal connectors between extreme points of mountains and valleys on adjacent rings. The stent is less prone to shorten when radially expanded, is longitudinally flexible in both its radially compressed state and in its expanded state, and provides a better framework. On the other hand, since the longitudinal fasteners centrally located on struts conventionally contain more metal than the short ones, the presence of extrinsic longitudinal fasteners can interfere with squeezing the stent to the desired compressed diameter.

The longitudinal connecting element 36 contains two curved segments 6a , Optionally includes the longitudinal connector 36 a straight segment 6b that is substantially parallel to the longitudinal axis 8th of the stent 3 is. The straight segment 6b Keeps the mountain and valley extremes on adjacent rings far enough apart so that they do not bother each other, and the curved segments 6a promote the nesting of the braces in the compressed form. The straight segment 6c is between the turning point 5a or 5b and the curved segment 6a arranged and is substantially parallel to the strut 34 , The short section of the rings 30a -B at the turning points 5a and 5b which extends substantially around it has a circumferentially measured length approximately equal to a width of the longitudinal connector to which it is connected.

This favors the vessel through the expanded stent 3 provided scaffolding, since the longitudinal connecting elements closely with the waveform of the rings 30a -B can be put into a nested arrangement when the stent is on the balloon 4 of the catheter 2 squeezed. Only one longitudinal connector is at one of the inflection points 5a -B connected. This makes the turning point 5 to a "dead end" in the longitudinal extent of the longitudinal connectors 36 for the stent 3 and allows some of the bending forces, which are not absorbed by the longitudinal connector itself, through the rings 30a -B to be absorbed, with which it is connected. The number of longitudinal connection elements 26 between two adjacent rings is preferably two or three.

With view on 1 and 5 In yet another embodiment of the invention, various alternative design features of a stent 3 shown manufactured according to the present invention, as well as features which do not fall within the scope of the invention. It should be understood that 5 does not purport to represent a single stent design, but instead presents in a single drawing various design features that can be used alone or in combinations to form a stent 3 manufacture. For example, one or more of the means for longitudinally connecting two rings, which in 5 are shown used to the rings 10a c, 20a -C, and 30a -C to connect, as in the 2 - 4 is shown to a stent 3 to produce the invention.

The Rings 40a -C in 5 are of nested closed elements 50 made by short straight peripheral fasteners 51 are connected. Closed elements 50 are through opposing curved mountain and valley segments 43a -B formed by shorter curved struts 44a and longer curved struts 44b connected, creating a V-shaped interstitial gap 52 is defined, which is substantially symmetrical to a line 57a is perpendicular to the longitudinal axis 8th of. stents 3 is. Within a ring, circumferential connecting elements extend 51 between shorter struts 44a and longer struts 44b the surrounding adjacent closed elements 50 , Circulating fasteners 51 connect surrounding adjacent sealed elements 50 at the low point or "bottom" of the V-shape. The closed element 50 contains a dent or indentation 60 on the shorter strut 44a Opposite to the point on the bracing 44a is arranged, on which the peripheral connecting element 51 attached, as in the magnification GG in 5 is shown. The bump 60 serves to reduce the amount of metal at the junction, thereby improving the longitudinal flexibility of the stent during delivery and reducing the stress due to radial expansion of the stent. The bump 60 is manufactured so that the width 62 the longer strut 44b at the bump 60 essentially equal to the width 64 a central portion of the strut element 44b is.

Two different ring orientations are in 5 shown. The Rings 40a and 40b are arranged in a parallel zig-zag configuration and the rings 40b and 40c are arranged next to an antiparallel zig-zag configuration. All three rings 40a -C are mirror images of their neighboring rings or ring.

Several different types of longitudinal links are in 5 shown. At the longitudinal junction AA (see magnification), are parallel rings 40a and 40b integral with the opposite curved mountain segment 43a or the curved valley segment 43b of the longitudinal neighboring mountain 41 or Tals 42 in the area 59a connected according to the invention; no longitudinal connection segment is used. The struts 44a and 44b contain curved segments 58a respectively. 58b that cause the mountain 41 and the valley 42 diametrically opposite each other.

In the longitudinal joint BB (see magnification), which is not within the scope of the invention, the rings are 40a and 40b on a longitudinally adjacent mountain 41 and valley 42 by a longitudinal connecting element 46a connected. One end of the longitudinal connecting element 46a is on the longer strut 44b of the ring 40a at a location near or adjacent to the curved mountain segment 43a attached. A longitudinal connecting element 46a is therefore at the "bottom" of the "V", which by the closed element 50 is formed, fixed so as not to disturb the interlaced V (zigzag) pattern. The other end of the longitudinal connection lements 46a is in the ring 40b in an analogous place on the longer strut element 44b near or adjacent to the curved valley segment 43b of the ring 40a attached. The longitudinal connecting element 46a contains a curved segment 56a disposed in a central portion thereof and of two substantially straight sections 54 which are substantially perpendicular to the longer struts 44b of the closed element 50 are flanked. The curved segment 56a is essentially symmetrical to a line 57b perpendicular to the longitudinal axis 8th of the stent 3 is. At a longitudinal joint CC are the rings 40a and 40b thus integral to the opposite curved mountain segment 43a or the curved valley segment 43b of the longitudinal neighboring mountain 41 or Tals 42 in one area 59b connected. The struts 44e and 44f are longer than corresponding struts 44a and 44b to the curved mountain segment 43a and the curved valley segment 43b to allow to meet each other.

The antiparallel rings 40b and 40c are by longitudinal fasteners 46b -D connected. In the longitudinal connection DD (see magnification) is the longitudinal connecting element 46b essentially straight and parallel to the struts 44g and 44h of the mountain 41 and the valley 42 ; in this sense, it is analogous to the longitudinal connector 26b in 3 , The Rings 20a -C in 3 are in phase, while the rings 40b -C are mirror images of each other. If the longitudinal connecting element 46b short is how in 5 is shown, the braces must 44g -H closer than corresponding struts 44a -B. If the longitudinal connecting element 46b long enough (not shown), the bracing can 44g -H in length equivalent to the struts 44a -B.

At the longitudinal joint EE (see magnification), which is not within the scope of the invention, is a longitudinal connecting element 46c at one end with the longer strut 44b of the ring 40b at a location near or adjacent to the curved mountain segment 43a connected and at the other end with an analogous location on the longer strut 44b of the ring 40c near or adjacent to the curved valley segment 43b , The longitudinal connecting element 46c includes two curved segments 56b that is a central segment 56c flank, which is oriented substantially in the circumferential direction.

At the longitudinal connection FF, a longitudinal connecting element extends 46d between the extreme points of the longitudinally aligned mountain 41 on the ring 40b or the valley 42 on the ring 40c , The longitudinal connecting element 46d includes two curved segments 56d which is an optional central segment 56f flank, which is oriented substantially in the circumferential direction. The curved segments 56b favor the tendency of the stent 3 to flex longitudinally when exposed to bending forces, such as those encountered during delivery of the stent 3 and a catheter 2 occur through a tortuous coronary artery.

With view on 1 and 6 is a complete pattern of a stent 3 for a coronary artery application which is substantially the same pattern as described above in connection with 2 was discussed. The stent 3 has a length "A" which, in a coronary artery application, could be about 8 to 42 mm (and about 15-25 mm as shown), although those skilled in the art will recognize that the pattern may be designed to have many lengths. The dimension "B" indicates the circumference of the stent 3 for coronary use, which is about 3-7 mm, and a crimped diameter for the stent 3 of about 1-2 mm. The dimension "C" refers to the width of one of the rings, which in this example could be in the range of about 0.08 to 0.12 mm. The dimension "D" refers to the amplitude of one of the rings and in this example could be in the range of about 0.75 to 2.5 mm. The dimension "E" refers to the mountain-to-mountain spacing for the rings and may be in the range of about 1-3 mm in this example. The dimension "F" refers to the width of a longitudinal connector and could be about 0.06 to 0.1 mm in this example. Radiopaque markers 9 are at opposite ends of the stent 3 arranged to allow the doctor to determine the position of the ends of the stent 3 to accurately identify fluoroscopically while the stent 3 is placed in the patient. The markers 9 may take the form of a thin gold disk placed in a portion of the pattern. The markers 9 have their highest fluoroscopic visibility when looking directly at the flat plane of the disc and lower visibility when viewed on the edge of the disc. Therefore, the markers 9 be aligned with each other so that both are visible with the same intensity, regardless of how the rotational orientation of the stent is (as in 6 shown), or spaced (not shown) from each other, to allow at least one marker 9 always considered in its most observable or observable flat orientation. More markers can be added to the in 6 be added so that each end of the stent 3 Having two or more markers in a relatively spaced position, which then allows one of the markers at each end to always be readily monitored no matter what rotational orientation the stent 3 having. The dimensions "G" and "H" indicate the diameter of the radiopaque markers and the width of the portion of the annulus that holds the marker.

With view on 1 and 7 is a complete pattern of a stent 3 for a coronary artery application which is substantially the same pattern as above in connection with 3 was discussed. Similar structures are with the same dimension symbols ("A" to "F") as in FIG 6 and the dimensional ranges for the stent 3 who in 7 are substantially the same as those of the stent 3 who in 6 is shown. This stent 3 can be made by laser cutting from a tube of stainless steel or other suitable material by methods well known to those skilled in the art. A radiopaque marker, such as the in 6 illustrated radiopaque marker may be at one or both ends of the stent 3 from 7 be inserted even though he is in 7 not shown.

With view on 1 and 8th is a complete pattern of a stent 3 for a coronary artery application not within the scope of the invention. Similar structures are with the same dimension symbols ("A" to "F") as in FIG 6 and the dimensional ranges for the stent 3 who in 8th are substantially the same as those for the stent 3 who in 6 is shown. This stent 3 may be made by laser cutting from a stainless steel tube or other suitable material by methods generally known to those skilled in the art. A radiopaque marker, such as the radiopaque marker, which in 6 can be shown at one or both ends of the stent 3 in 8th be inserted even though he is in 8th not shown.

The radially outward directed force exerted by the stents according to the present invention, serves two functions. One feature is that body lumens are against one inside directed radial force, e.g. a spasm of keeping open, as well as a narrowing of the passage through the lumen by intimal Flaps or sections, e.g. by previous balloon angioplasty generated, prevent. Another feature is the position of the stent within the body lumen to fix, by intimate or close contact between the stent and the walls of the lumen. The outward directed forces have to but not that big to avoid traumatizing the lumen walls through the stent.

The Diameters of some preferred stents are, when in the compressed condition for feeding to a desired Place near a body lumen are, traditionally around twice to six times the diameter of the stents when they are in their expanded state before squeezing are reduced. For example can typical stents have a compressed outer diameter of about 1 mm until about 3 mm for feeding and an expanded outer diameter in a body lumen of about 3 mm to about 15 mm when in a large arterial vessel from the Compression solved become. Some preferred stents used in coronary arteries can, can a compressed outer diameter of about 1 mm and an extended outer diameter in a body lumen of about 6 mm.

In addition to the ranges in diameter, it should also be appreciated that the stents of the present invention may have any desired longitudinal length as needed for a particular application. Furthermore, although the stents shown in the 6 - 8th a plurality of successive ring members, it will be appreciated that some stents could be made with only one ring member according to the present invention (in this case, no longitudinal members would be needed to connect adjacent support sections). Preferred materials for making stents according to the present invention include those materials which have the desired functional properties in terms of biocompatibility, modulus of elasticity, etc. Materials for both balloon expandable stents and self-expanding stents are known in the art, and the device of the invention is not intended to be limited by any particular single material. Similarly, the preparation of the stents according to the present invention may be carried out by any of a variety of methods well known to those skilled in the art. See, for example, U.S. Patent No. 5,776,161 to Globerman.

Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms, for example, it will be appreciated that although the stents include one or more ring members as described herein, the stents made in accordance with the present invention may be any Number of desired ring elements needed to obtain a stent of desired length. Furthermore, it is recognized that the figures are only schematic, and that the relative dimensions of the various features illustrated are not so are seen to limit the scope of the present invention. Accordingly, the present invention is not limited to the specific embodiments described in detail herein.

Claims (14)

A medical device comprising: a catheter ( 2 ) and a radially expandable stent attached to the catheter ( 3 ), wherein the stent comprises a hollow cylindrical body with first and second rings ( 10a C) extending around the cylindrical body, each ring forming a wave-like series of mountains ( 11 ) and valleys ( 12 ) comprising struts interconnecting curved, alternating mountain and valley segments within the ring ( 14 ) are formed, wherein the struts a first curved segment ( 15a ) which is substantially symmetrically curved about a single circumference of the stent such that the peaks and valleys within a ring form a nested zig-zag pattern; characterized in that the first and second rings are directly and firmly attached to respective opposite mountain and valley segments ( 43a . 43b ) are connected ( 59a ). Medical device according to claim 1, wherein the struts ( 14 ) further comprise a second curved segment which is close to a curved mountain or valley segment ( 13a -B) is positioned. A medical device according to claim 1 or 2, wherein the first and second rings ( 10a C) are arranged in a parallel zig-zag pattern relative to each other. A medical device according to claim 1 or 2, wherein the first and second rings ( 10a -C) are arranged in an anti-parallel zig-zag pattern relative to each other. Medical device according to claim 1 or 2, wherein the mountains ( 11 ) of the first ring ( 10a ) are longitudinally aligned with the valleys ( 12 ) of the second ring ( 10b ). Medical device according to claim 1 or 2, wherein the mountains ( 11 ) of the first ring ( 10a ) are not longitudinally aligned with the valleys ( 12 ) of the second ring ( 10b ). Medical device according to claim 1, 2 or 6, wherein the mountains ( 11 ) of the first ring ( 10a ) longitudinally aligned with the mountains ( 11 ) of the second ring ( 10b ). Medical device according to one of the preceding claims, further comprising at least one radiopaque marker ( 9 ). The medical device of any one of the preceding claims, wherein the radially expandable stent comprises a balloon expandable stent (US Pat. 3 ). The medical device of any one of claims 1 to 8, wherein the radially expandable stent is a self-expanding stent ( 3 ). Medical device according to one of the preceding claims, wherein at least one strut ( 34 ) on each of the first and second rings ( 30a , b) also a turning point ( 5 ) positioned near a central portion of the brace. The medical device of claim 11, wherein the inflection point (s) ( 5 ) near the first curved segment ( 35a ) of the bracing ( 34 ) is / are positioned. A medical device according to any one of the preceding claims, comprising: the first and second rings each having a plurality of closed members ( 50 ), each closed member comprising a mountain and a valley ( 43a -B) by a longer strut ( 44b ) and a shorter strut ( 44a ) connecting the curved mountain and valley segments, the longer and shorter strut each comprising the curved segment that is substantially symmetrically curved about a single circumference of the stent such that the peaks and valleys within the annulus form a nested zig -Zack structure, and further comprising circumferential connecting links ( 51 ) between the longer strut and the shorter strut of the circumferentially adjacent closed members ( 50 ). Medical device according to claim 13, wherein the closed links ( 50 ) further a recess ( 60 ) positioned on the shorter strut so that the indentation is substantially circumferentially aligned with the perimetral link attached to the shorter strut.